The present invention generally relates to material displacement apparatus and, in a preferred embodiment thereof, more particularly relates to apparatus for releasably coupling a replaceable excavation tooth point to an associated adapter nose structure.
A variety of types of material displacement apparatus are provided with replaceable portions that are removably carried by larger base structures and come into abrasive, wearing contact with the material being displaced. For example, excavating tooth assemblies provided on digging equipment such as excavating buckets or the like typically comprise a relatively massive adapter portion which is suitably anchored to the forward bucket lip and has a reduced cross-section, forwardly projecting nose portion, and a replaceable tooth point having formed through a rear end thereof a pocket opening that releasably receives the adapter nose. To captively retain the point on the adapter nose, aligned transverse openings are formed through these interengageable elements adjacent the rear end of the point, and a suitable connector structure is driven into and forcibly retained within the aligned openings to releasably anchor the replaceable tooth point on its associated adapter nose portion.
Connector structures adapted to be driven into the aligned tooth point and adapter nose openings typically come in two primary formsxe2x80x94(1) wedge and spool connector sets, and (2) flex pin connectors. A wedge and spool connector set comprises a tapered spool portion which is initially placed in the aligned tooth and adapter nose openings, and a tapered wedge portion which is subsequently driven into the openings, against the spool portion, to jam the structure in place within the openings in a manner exerting high rigid retention forces on the interior opening surfaces and press the nose portion into a tight fitting engagement with the tooth pocket.
Very high drive-in and knock-out forces are required to insert and later remove the steel wedge and typically require a two man effort to pound the wedge in and outxe2x80x94one man holding a removal tool against an end of the wedge, and the other man pounding on the removal tool with a sledge hammer. This creates a safety hazard due to the possibility of flying metal slivers and/or the second man hitting the first man instead of the removal tool with the sledge hammer. Additionally, wear between the tooth/adapter nose surface interface during excavation use of the tooth tends to loosen the tight fit of the wedge/spool structure within the tooth and adapter nose openings, thereby permitting the wedge/spool structure to fall out of the openings and thus permitting the tooth to fall off the adapter nose.
Flex pin structures typically comprise two elongated metal members held in a spaced apart, side-by-side orientation by an elastomeric material bonded therebetween. The flex pin structure is longitudinally driven into the tooth and adapter nose openings to cause the elastomeric material to be compressed and resiliently force the metal members against the nose and tooth openings to retain the connector structure in place within the openings and resiliently press the adapter nose portion into tight fitting engagement with the interior surface of the tooth socket.
Flex pins also have their disadvantages. For example, compared to wedge/spool structures they have a substantially lower in-place retention force. Additionally, reverse loading on the tooth creates a gap in the tooth and adapter nose openings through which dirt can enter the tooth pocket and undesirably accelerate wear at the tooth/adapter nose surface interface which correspondingly loosens the connector retention force. Further, the elastomeric materials typically used in flex pin connectors are unavoidably subject to deterioration from hot, cold and acidic operating environments. Moreover, in both wedge-and-spool and flex pin connectors relatively precise manufacturing dimensional tolerances are required in the tooth point and adapter nose portions to accommodate the installation of their associated connector structures.
Proposed solutions to these various connector-based problems, limitations and disadvantages in excavation tooth point/adapter assemblies have included wedge-shaped connector members which are inserted into the aligned point and adapter nose openings having complementarily tapered configurations, with the inserted connector being resiliently biased in a longitudinal xe2x80x9ctighteningxe2x80x9d direction relative to the point and adapter nose by a lock member carried by the connector member. The lock member is rotatably and sealingly received within an end of the connector member, bears against a portion of the tooth point, and is spring-biased longitudinally outwardly from the connector member. An example of this wedge-shaped type of connector structure is illustrated and described in U.S. Pat. No. 6,108,950 to Ruvang.
This particular wedge-shaped type of connector structure at least substantially reduces various of the problems, limitations and disadvantages discussed above in conjunction with conventional flex pins and wedge and spool connector sets. However, it has several limitations of its own. For example, due to the wedge shape of the connector member, excavating loading forces exerted on the connector member can generate a substantial axial force component on the connector member which can, in certain instances, damage the lock member and permit the connector member to be expelled from the tooth point and adapter nose openings. Moreover, because the spring-biased lock member is permitted to move into and out of the connector member, dirt may be drawn into the interior connector/lock member surface interface area and substantially degrade the seal carried by the lock member. Further, with the lock member maintained in its unlocking position for extended periods of time (for example when the overall connector structure is being stored prior to use), an elastomeric portion of the lock member detent portion is maintained in compression and can obtain an undesirable compression set.
It can be seen from the foregoing that it would be desirable to provide improved excavating tooth connector apparatus that eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages associated with conventional excavating tooth and other material displacement equipment connector apparatus of the general type described above.
In carrying out principles of the present invention, in accordance with a representatively illustrated embodiment thereof, a specially designed connector assembly is used to releasably retain an excavating wear member, representatively a replaceable tooth point, on a support structure, representatively an adapter nose.
The connector assembly, in the representatively illustrated embodiment thereof, includes (1) an elongated flat connector member extending along a longitudinal axis and having a flat exterior side peripheral portion extending between opposite first and second ends and circumscribing the longitudinal axis in a parallel relationship therewith, and (2) a locking member rotatable received in the first connector member end and being rotatable between locking and unlocking positions in which a locking tab portion of the locking member respectively projects laterally outwardly beyond the connector member side surface periphery, and an unlocking position in which the locking tab does not project laterally outwardly beyond the connector member side surface periphery.
A detent structure within the interior of the connector member releasably retains the locking member in either selected one of its locking and unlocking positions. The locking member has no resilient force exerted thereon parallel to the length of the connector member in either of the locking and unlocking positions of the lock member, and the detent structure substantially prevents any appreciable relative movement of the lock member and the connector member parallel to the longitudinal axis of the connector member when the lock member is in either of its locking and unlocking positions. The detent structure representatively includes a rigid detent member carried by the lock member and having an associate resilient portion, and first and second circumferentially spaced detent openings disposed within the connector member interior for respectively receiving the detent member when the lock member is in its locking and unlocking positions. The resilient portion of the detent structure is in an essentially relaxed state when the lock member is in either of its locking and unlocking positions.
With the tooth point telescoped onto the adapter nose, side wall connector openings in the tooth point aligned with a connector opening transversely extending through the adapter nose, and the lock member in its unlocking position, the connector assembly is inserted into the connector openings until the opposite ends of the connector member are disposed in the opposite tooth point connector openings to thereby block forward removal of the tooth point from the adapter nose. The locking member is then rotated to its locking position. After this is done, abutment surface areas within the interior of the tooth point/adapter assembly prevent the installed connector assembly from moving outwardly through either tooth point connector opening. Representatively, these abutment surface areas include (1) a first abutment surface defined in an interior side surface recess of a first one of the two tooth point side wall connector openings into which the locking tab is moved when rotated to its locking position, the first abutment surface blocking the locking tab, and thus the entire connector assembly, from moving outwardly through the first tooth point connector opening, and (2) a second abutment surface formed on a side wall portion of the tooth point which extends into the second tooth point connector opening, reduces its cross-sectional area relative to that of the first tooth point connector opening, and blocks the installed connector assembly from moving outwardly through the second tooth point side wall connector opening.